THIS invention relates to a prop headboard.
It has already been proposed to preload a mine support prop by providing it with a transversely extending headboard which supports an inflatable grout bag. In practice, the prop is erected upright on the footwall of a mine working, with the headboard spanning transversely across the head of the prop. The grout bag is placed on top of the headboard and is inflated with a suitable grout under pressure. The inflation of the bag with grout, which is normally of a rapid setting type, causes the bag to expand forcibly against the handing wall and to apply an axial preload force to the prop. The axial preloading of the prop enables it immediately to take the loading applied by the handing wall.
A number of different headboard arrangements have already been proposed but are, generally speaking, rather expensive to manufacture. It is an objective of the present invention to provide a headboard which can be constructed at modest cost.